1. Field of the Invention
This disclosure relates to the field of exercise machines. In particular, to exercise machines designed to perform different exercises (such as converging and diverging or push and pull strength exercises) with arms which follow a fixed or guided path.
2. Description of the Related Art
Over recent years, as physical fitness has become an ever more popular pursuit, there have evolved a plurality of exercise machines upon which exercises can be performed by a user. One type of exercise machine is the strength machine which is designed to improve muscle strength and tone by having the user utilize certain muscle groups to pull, push or otherwise perform work on some type of resistance mechanism built into the machine.
As the nature of exercise has become more fully understood, different types of exercise machines have been developed to provide for more effective training. Originally, strength training was performed by the lifting of free-weights. While simple to understand and operate, free-weights had inherent dangers in their use, and, although conceptually simple, were often hard to use correctly without trained instruction. In order to get the best toning or shaping results out of particular exercises, it is desirable that muscle groups be isolated so that the intended muscle group is exercised by the exercise, as opposed to exercising an unintended muscle group. With free-weights it was often not possible to perform exercises that isolated the desired muscle groups, and even if it was possible, it was often difficult to know how to perform the exercises correctly without specific instruction. As strength machines have evolved, they have tried to improve both the safety of performing different exercises, and the effectiveness of the exercise to isolate different muscle groups.
To most effectively isolate and exercise particular muscle groups, it is desirable that the exercise machine be arranged so that the user is limited in their motion to that which effectively performs the desired exercise on the desired muscle groups. This is generally performed by the selection and arrangement of two components of the machine. Firstly, there is a bench, seat or other structure which supports the user's body. For some exercises, this may be as simple as the floor upon which the machine rests, while for others adjustable benches may be provided to position portions of the user's body relative to appropriate pieces of the exercise machine. This component helps to get the user in a comfortable position where they can operate the moving portions of the machine, and place them in a position relative to the moving parts of the machine so that they manipulate those parts to perform the exercise.
The other component is the moving portion of the machine and is generally in the form of “arms” or other objects which are arranged in a manner to be engaged by the user at a certain point (such as a grip or handle), and then be moved by the user along a predetermined path or a guided path resisted by the machine. When the two components of the machine are used together correctly, the user is therefore positioned in such a manner that when the grip is moved by the user on the bench, the predetermined or guided path dictates the motion of the handle and, if the machine is well-designed, exercises the intended muscle group. This results in the user both isolating a muscle group and performing a safer exercise motion.
The difficulty with the design of strength machines, however, is that they generally need to be both flexible to perform multiple exercises, and limited to guide a user to perform an exercise correctly. As more has become known about the motion of particular exercises, this has led to a difficulty in finding exercise motions which can be incorporated into the same machine. Specifically, different types of exercise generally have different motions of the grips or handles and therefore the arms need to have different paths. With free-weights, the user can freely position the weights relative to their body, allowing them to perform numerous exercises, but at the same time, the user is not guided to perform any of the exercises correctly because the weights can be freely maneuvered. Strength machines, on the other hand, can often be designed to guide the particular motion of the user, but this limits the number of exercises which can be performed on the machine. This is particularly problematic when space for exercise machines is limited, such as for most individuals in their homes, and even for the majority of gyms or workout facilities.
One significant problem which has existed with strength machines is to incorporate both push-type and pull-type exercises in the same machine, without the inclusion of multiple sets of arms for the user to interact with significantly increasing the complexity of the machine. For instance, when exercising the upper torso it is desirable to perform push-type exercises where the arms are pushed away from the body against resistance and pull-type exercises where the arms are pulled toward the body against resistance.
The duality of exercise discussed above exists because muscle groups generally operate in pairs. In particular, individuals generally have two sets of muscles which operate in conjunction with each other. One set acts to move in one direction, while the other acts to move in the opposing direction. Since muscle generally performs work by contracting, the two muscle groups act in concert with one group contracting (performing work) while the other group expands (essentially resting).
To increase strength and/or tone in any particular muscle region (set of two or more muscle groups such as the torso) it is therefore desirable to be able to perform different types of exercise motions. This, however, requires a machine capable of providing resistance to both a push and pull motion (or to motion in different directions) to related or different muscle groups. A difficulty arises because many resistance mechanisms generally only provide resistance to motion in one direction (e.g. the resistance is opposing the lifting of a weight from its resting position, as compared to returning it to its resting position). The commonality of this type of resistance has generally required exercise machines that provide a user with both push and pull motion to either have additional arms for each exercise so that the arms can follow different paths—which necessarily increase their size, expense and complexity—or to have complex mechanisms for the arm motion allowing users to connect and disconnect components to accomplish different exercises. This leads to increased difficulty of construction and use, increased expense, and often an increased risk of failure.
Further, the range of motion utilized when a user is performing a pull motion is often different from the range of motion of a user performing a push motion with a related muscle group. For example, a user performing a chest press will generally begin the exercise with their hands near their chest, however in the corresponding rowing movement, the user will often end the exercise with their arms lower, near their upper mid-section. This difference exists even though the general motion of both exercises is basically perpendicular to the plane of the body and may exist due to differing rotation in the arms or hands when performing the different exercises comfortably.
Still further, exercises are generally not performed using static patterns where the hands maintain a constant position relative to each other, but are preferably carried out with the hands either converging on each other or diverging from each other.